[Python-Dev] Rewrite @contextlib.contextmanager in C

[Nick Coghlan]

On 9 August 2016 at 23:26, Nick Coghlan <ncoghlan at gmail.com> wrote:

> On 9 August 2016 at 06:18, Guido van Rossum <guido at python.org> wrote:
>
>> I think Nick would be interested in understanding why this is the case.
>> What does the decorator do that could be so expensive?
>>
>
> Reviewing https://hg.python.org/cpython/file/default/Lib/contextlib.py#l57,
> Chris's analysis seems plausible to me
>

Sorry Wolfgang - I missed that Chris was expanding on a comparison you
initially made!

Either way, I agree that aspect does make up the bulk of the difference in
speed, so moving to C likely wouldn't help much. However, the speed
difference relative to the simpler warppers is far less defensible - I
think there are some opportunities for improvement there, especially around
moving introspection work out of _GeneratorContextManager.__init__ and into
the contextmanager decorator itself.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
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